Do you have spare space in your garden that is taken over by weeds? Try summer cover crops during the growing season to enrich your soil for subsequent planting and to smother the weeds. Cover crops are selected species of plants that are grown to improve the soil structure, retain soil nutrients, prevent erosion, and out-compete weeds from taking over the garden.

Depending on the planting season, there are two different types of cover crops – summer cover crops and winter cover crops. Summer cover crops are warm-season species planted from June through mid-August and are killed by first frost in fall season. They germinate quickly, enrich the soil by its biomass, cover the bare soil, and smother the weeds. However, if they are planted late in the season, they may not be able to produce enough biomass and soil cover.

One of the summer cover crops that might be highly beneficial to gardeners is buckwheat, as it suppresses the weeds with its fast, vining growth. It germinates quickly as long as the soil temperature is above 55°F, and it doesn't need much water or fertilizer for its growth. It can scavenge soil phosphorous and release it back into the soil as nutrients when its biomass is tilled. They produce ample fibrous root systems that loosen the soil and make it easy to till underneath the soil bed. Buckwheat prefers to grow in a full sun area and will not tolerate wet soils.

Before you seed the buckwheat, rake the soil and remove any large debris and stones. Spread about 2 pounds of seed per 100 square feet (a 10-foot by 10-foot area) and rake the seed back into the soil to a maximum depth of 1 inch. Water the seeded area lightly.

It takes three to five days for the seed to germinate. It reaches flowering stage about 5 weeks after seeding. Buckwheat flowers are magnets for bees and other pollinators. However, it will also attract the invasive Japanese beetle.

You should not let buckwheat seed, as it can become a weed. Therefore, it's recommended to till the buckwheat into the soil within a week after flowering. After tilling, wait three weeks for its biomass to decompose before planting fall season crops.

Other summer cover crops to try in the garden area are soybeans, which can fix nitrogen in the soil. Plus, edible soybeans like edamame can also be harvested for its pods.

Winter cover crops are cool season species that are planted in late August through mid-September and are tilled the next spring. Common cool season cover crops are oats, oilseed radish and berseem clover.